HELP! riddle me this...

[EliteConcept]

i put my 15in rims on my truck today. i had the 16in tri spoke rims on it.
tires are inflated to about 39-40 psi (max is 44)
So anyways i started going down the road and once i hit about 30 i had a loud humming coming from the front end. Its very noticable, and you can feel it on your feet on both the passenger and driver side.

It didn't do this with the 16in rims, so it has to have something to do with the rims. The 15in rims were in storage for about 6 months, i was thinking maybe during putting them in storage i messed up the balance of the rims...

what could it be? what should i do?

thanks in advance

 

[Pheonixx77]

try having your tires balanced for the rims...but the truck would shake and shimmy ALOT mine did this once after i rotated the tired until i took it to a shop and had the tires balanced. this might fix it it might not.

 

[mhn3773]

mabey lower the tires psi to like 33? also mabey they arent balanced anymore like u said try moving them like front left on rear right see if it changes or goes away

 

[Alec]

Yup, you need to get the new rim/tire combo balanced.

Also lower your air pressure, this is the 4th post I've seen today on an auto forum with someone thinking it's a good idea to fill the tire close to max psi. I'm sorry, but it's not.

 

[MONMIX]

You need to let out the summer air and put in the winter air

 

[EliteConcept]

well i had the tire pressure at 30, but when i upped it to 39/40 the sound went away some...i'll let some out drop it to about 35/36

they need balanced huh? i'll have to get that done soon

 

[Pheonixx77]

yeah seeing as how they are not balanced i would avoid drving above 45-50 mph for now....you may break nmore than your truck...when mine was unbalanced i drove it on expressway and OUCH was it tough to drive...good thing it was a 1 exit trip

 

[EliteConcept]

while driving around town i was doing 45 or so and steering wasn't too bad...

 

[Bill Kemp]

It could be that the tires are cupped on the edges. When you air them up they are not riding on the edge but the center. Take a look see...

 

[chris c]

Originally posted by Bill Kemp
It could be that the tires are cupped on the edges. When you air them up they are not riding on the edge but the center. Take a look see...

agreed, it is more likely a wear pattern on the tires causing the humming as opposed to out of balance tires...

 

[EliteConcept]

is that bad if it is?

 

[expo5.0]

that sounds most likely that they are cupped- if that is the case your pretty much screwed they will continue to wear in the wrong way and in fact the cupping will only get worse.

 

[IAmTodd]

I agree with the cupped tires. My winter tires do that and I'm not looking forward to putting them on Once you get them rotated a couple times it will eventually wear down and be a low hum. Just bear with it!

 

[EliteConcept]

so its not dangerous or anything?

yeah these are my winter tires also.. i had time this weekend (which is rare) so i put them on

 

[IAmTodd]

I ran mine full time for a year and a half before I got my BFGs and I had no problem with them. I don't see what could be dangerous, though I don't know much about tires. Now I just need to find time to put mine on, calling for snow flurries this week

 

[Bill Kemp]

I had a set of cupped goodyears. I had them turn the tire around on the rim. Put the raised letters on the inside instead of the outside. Helped the noise a litttle & helped even out the wear. But once they are cupped they will always be noisey

 

[X24]

Can someone explain exactly what "cupped" means and how they get that way? Does it happen when the tires are in storage?

 

[expo5.0]

what happens is if the tires get a little out of balance they start wearing funny in a spot. then once one spot is screwed up it messes up the smooth rotation of the tire and it starts oscillating. its the same sort of mechanism that leads to bumps on a dirt road or in a more exaggerated manner bumps on a snowmobile trail. once it starts the rotation begins to have oscillations that only get worse over time. switching the tires around could help though for sure, but you can see how it can never realy be fixed.

 

[expo5.0]

storage could cause it, but its more likely due to running too little psi on the highway

 

[Bill Kemp]

Storage cant and didnt cause cupping. Tires were cupped when they were taken off. It happens gradually so he didnt notice the increase in tire noise.
Worn shocks, ball jionts ect. cause cupping. Some tires are more prone to cupping than others. Some cars are more prone than others. I never had cupped tires untill I got an X. I replaced the shocks & ball joints, as they were needed, but the tires continued to cup. Once they start they dont quit.